The present embodiments relate to a power electronics assembly for a magnetic resonance device.
Magnetic resonance devices according to the prior art have become widely known. In these magnetic resonance devices, a transmitting antenna (e.g., a transmit antenna) that excites spins of an object to be examined that is oriented in a main magnetic field is provided. High frequency, high power pulses are applied to the transmitting antenna. The high power pulses are made available by a transmitting unit (e.g., a transmit unit) to a magnetic resonance device, which includes a power amplifier unit.
The transmit units or power amplifier units of the magnetic resonance device are examples of power electronics assemblies in a magnetic resonance device. Power electronics components, in which a high level of dissipation is to be achieved in a minimal volume, are involved. Effective cooling is to be provided. The requirements are increased if the power electronics units are to be realized to be as structurally compact as possible. A cooling solution should also be immune to the leakage fields of the main magnet of the gradient system and the high frequency transmit antennae. No high frequency fields may be emitted, in order to not negatively influence the magnetic resonance receive signal originating from the object. The cooling system is to work as noiselessly as possible and demonstrate a high level of robustness against coolant pressure fluctuations and different coolant mixtures. If the unit is realized as part of the screened housing, the cooling system should also enable high frequency shield attenuation and voltage protection against the cooling water as well as having a high level of mechanical robustness.
It is known for high frequency-power assemblies (e.g., the high power components) to be cooled with air. This demands large heat sinks or a powerful stream of cooling air from a powerful fan. Liquid cooling systems are also known. In a liquid cooling system, a tubular cooler or a micro channel cooler is arranged in the housing. The tubular cooler or the micro channel is connected to the heat-generating components via a heat dissipation mechanism. Both of the solutions described here pose large space requirements, as, for example, the air-cooled solution calls for the configuration of most of the power components in a utility room; the necessary cooling performance thus cannot be achieved at the magnet. The described water cooling also takes up such a large volume that the water cooling cannot be realized at the magnetic resonance magnet.